Earlier this month, Iran said that it had decoded and released footage from a U.S. drone that it downed more than a year ago.

The black and white aerial footage, which Iran claims was from a RQ-170 spy plane, was aired by Iranian news agencies and placed on YouTube.

Iran said it downed the drone on December 4, 2011, near Kashmar in the country's northeast, some 225 kilometers (140 miles) from the border with Afghanistan.

At the time, U.S. officials acknowledged that the drone was missing and President Barack Obama asked Iran to return it.

Iranian military officials vowed not to return the plane.

In December 2012, Iran's navy claimed that it had captured another U.S. drone, after it entered Iranian airspace over the Persian Gulf.

However, a U.S. defense official, who could not be named because the official was not authorized to speak to the media, told CNN that whatever the Iranians claim to have, it is not an actively operating U.S. Navy drone.